Make common Python packages available to Python projects #14
Description
Some common packages such as isort, blue, flake8 etc. should be available to Python projects or Codebox's clients to lint code or something like that.
The packages should be installed in a different virtual environment directory that will be made available later to the jail environment through a directory called /.venv. This directory should also be added to the PATH environment variable to the jail environment.
Probably, the best way to install those packages is from the Dockerfile. Also, we might use a Docker volume to keep and update those packages.
It is worth investigating whether PYTHONPATH or PYTHONUSERBASE is the best envvar to keep the new path, or if PATH is enough.
Snekbox has a similar concept. See its README.